Scientific Study

BACKGROUND: Peanut is one of the eight major food allergens. Its allergen, Ara h 2, can be recognized by over 90% of serum IgE samples from peanut-allergic patients. Therefore, reducing the allergenicity of Ara h 2 is especially important. RESULTS: In the present study, polyphenol oxidase (PPO), a protein cross-linking reaction catalyst that acts on tyrosine residue, was used to modify Ara h 2. After cross-linking, the microstructure, digestibility, IgG binding capability, and IgE binding capability of Ara h 2 were analyzed. Cross-linking decreased the potential allergenicity of Ara h 2 by masking the allergen epitope, while the antigenicity of Ara h 2 slightly changed. After cross-linking, the apparent diameter of Ara h 2 was altered from 300 nm to 1,700 nm or 220 nm, indicating that polymerization could either be inter- or intramolecular. For the digestibility, cross-linked Ara h 2 was relatively more easily digested by gastric fluid compared with the untreated Ara h 2, but much more difficult in the intestinal fluid. CONCLUSION: The cross-linking reaction catalyzed by PPO, as a non-thermal process, may be beneficial for avoiding food allergy. The reaction could mask the allergen epitopes, decreasing allergenicity of Ara h 2.